(1) Field of the Invention
This invention relates to 1-(3-vinylphenyl)-1-phenylhydrocarbons and method for producing the same. More particularly, the invention relates to 1-(3-vinylphenyl)-1-phenylethylene and a method for efficiently producing the same, and further relates to 1-(3-vinylphenyl)-1-phenylethane which is used for preparing the former compound.
The 1-(3-vinylphenyl)-1-phenylethylene which is a new compound proposed in the present invention is used as an intermediate for economically preparing .alpha.-(3-benzoylphenyl)propionic acid (tradename: ketoprofen) represented by the following formula (IV) through .alpha.-(3-(1-phenylethenyl)phenyl)propionic acid or its alkyl ester which is represented by the following formula (III). The ketoprofen is a useful medicine for the relief of pain and inflammation.
Furthermore, the 1-(3-vinylphenyl)-1-phenylethylene can be efficiently prepared by dehydrogenating another new compound of 1-(3-vinylphenyl)-1-phenylethane. ##STR1## wherein R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ##STR2##
(2) Description of the Prior Art
There are proposed various methods for producing ketoprofen. Among them, typical methods are described in the following.
(1) 3-Benzoylpropiophenone is reacted with orthomethyl formate in the presence of thallium nitrate to produce the methyl ester of ketoprofen (British Pat. No. 2,019,393). ##STR3##
(2) 3-Benzylacetophenone is reacted with ethyl chloroacetate in the presence of a strong base to produce glycidic acid ester. This compound is then treated with an aqueous solution of sodium hydroxide to obtain a hydrolyzed and decarboxylated product of .alpha.-(3-benzylphenyl)propionaldehyde and it is further oxidized with potassium permanganate to obtain the ketoprofen (Japanese Laid-Open Patent Publication No. 55-36450). ##STR4##
With regard to the method (1), even though the reaction process is short, it cannot be said that the synthesis of the raw material is easy and safe because the toxic thallium compound is used. Furthermore, it cannot be said that the starting material used in the method (2) is easily available. Accordingly, these methods (1) and (2) are not satisfactory in view of industrial production.